The objective of this research is to study animal models of heriditary retinal degeneration to gain information useful to an understanding of human retinitis pigmentosa. More specifically, the retinal pigment epithelium (RPE) will be studied in cell culture. The retinal degenerations of the RCS rat and of the canine ceroid lipofuscinosis dog (CCL) are chosen for study. The phagocytic defect of the RCS rat RPE will be quantitatively measured and compared in serial cell culture RPE from RCS and congenic control animals. Rod outer segments and an artificial particle will be phagocytozed. RCS rat macrophage phagocytosis will be examined to see if the phagocytic defect extends to other naturally phagocytic cells. The accumulation of ceroid and lipofuscin in cultured RPE from CCL dogs will be studiedwith electronmicroscopy. Peroxidase will be measured in these cultures taken from proper genetic samples. The affect of exogenous peroxidase on this storage disease in vitro will be studied.